David o



(No Model.)

D. O. HOLMAN.

ROTARY ENGINE.

Patented Nov. 15,1881.

J. A @W e /k INVENTOR WITNESSES U ITED STATES PATENT FFICE.'

DAVID O. IIOLMAN, OF ADAMS, NEW YORK, ASSIGNOR TO HIMSELF AND THOMAS P. SAUNDERS, OF SAME PLACE.

ROTARY ENGINE.

SPECIFICATION formingpart of Letters Patent No. 249,620, dated November 15, 1881.

Application filed March 21,1881. (N0 model.)

To all whom it may concern Be it known that I, DAVID O. HOLMAN,.0f Adams, in the county of Jefferson and State of New York, have invented a new and useful Improvement in Rotary Steam -Engines, of whichthe following is a full, clear, and exact description.

This invention consists in a novel construction and, form of the cylinder and piston, and

certain details connected therewith, whereby an engine is produced which will run with equal facility in both directions, and whereby is produced what is practically two engines combined in one, which may be used either 1 5 separately or both together, as hereinafter m ore particularly described.

In the accompanying drawings, Figure l is a central vertical section of an engine constructed according to my invention. Fig.2 is a vertical section at right angles to Fig. 1. Fig. 3 shows the top of the steam chest removed and the valves in place therein. Fig. 4 shows the bottom of the steam-chest with the valves removed.

2 5 Similar letters of reference indicate corresponding parts.

A represents the frame of the engine, at the ends of which are standards B B of skeleton construction. Each standard B carries two 0 journal-boxes, D, furnishing bearings for two horizontal shafts, 0, one above the other. Each box D is longer than its diameter, so as to furnish a sufficiently broad bearing for its shaft, and it is held in place by two screws, d, passing through the standard from opposite directions. The two shafts O are geared together by gearing c, and the lowest shaft carries a driving-pulley, 0

The cylinder E is of a shape approximating to that of the Arabic figure 8that is to say, it describes in its outline two circles with their peripheries intersecting each other, the upper circle being smaller than the lower one. (The term cylinder is here used to designate that 4 5 part of the engine which performs the function of what is technically known by that name in steam -engines.) There are two of these cylinders E, separated from each other by a solid partition, f, and they are exactly alike, so that a description of one will apply to both. They are provided with cylinder-heads, c, which,

with the partition f, form a steam-tight casing. On the top of the casing so formed is located the steanrchest H, in which work slide-valves J,and the stems of said valves extend through 5 the chest and are connected to lex'ers K. The valve-chest H communicates with both cylinders by means of portsg g, two ports to each cylinder, and steam is supplied to the chest, through a po1t,g and exhausted therefrom through a port, g

In the cylinder E work two disks or solid wheels, L M, one above the other, keyed to and rotating with the shafts O, which said shafts work through stuffingboxes in the cylinderheads 0. The wheel L corresponds in size with the circle in which it works. The wheel M is of the same size as the wheel L for about threequarters ofits circumference, and the remaining quarter is of the same size as the circle in which it works, being composed of an areshaped extension, at, which constitutes the piston proper; and between the ends of this piston is a steam-space comprising an arc extending for about three quarters of a circle. The wheel L has a recess, 1, on one side, formed by cutting a segment from the periphery and curving the chord of said segment, so as to produce two depressions, I".

When the parts are in thepositions shown in Fig. 2 the port 9 on the left-hand side of the figure is the steam-port, and the other port 9 is the exhaust-port, and the wheels L M revolve in the directions indicated by the arrows. The live steam entering through the steam port 8 5 strikes the end of the piston m, while the recess Z acts as an abutment, and the wheels are caused to revolve. The faces of the wheels are in close contact with each other and prevent any back action of the steam. When the pis- 0 ton on hasmade a complete revolution from the point shown in the drawings it covers both of the ports 9; and in order that there may be no lateral pressure it is provided with perforations 0', through which steam may pass to the cylin- 5 der-head, and thus prevent loss of motion from friction. When the piston is over both ports the recess l is immediately above it, and the two parts engage with each other like gearing. As soon as the point 1 of the piston passes the exhaust-port g the steam begins to exhaust, and

as soon as said point passes the steamport g the piston begins to take steam. When the point f the piston reaches the exhaust-port it engages with a corresponding point at the end of the recess l, and the piston and recess remain engaged until the parts again reach the position shown. By moving the valve J to a position opposite to that shown the direction of rotation of the wheels L and M is reversed, and by placing it midway between said positions, so as to cover both steam-ports, the engine is stopped.

It will readily be seen that by operating both of the valves both engines may be used at the same time. When only half the power is required the steam may be out ofi' from one of the engines by simply closing the valve belonging to it. When both engines are used the pistons are diametrically opposite to each other, and when one is taking steam the other is exhausting, so that the engine is always in a condition for taking steam.

I am aware that gears, shaft, and partition have been used substantially as I use them; but I do not use a hollow hub in center of each cylinder for the shafts, because that renders it almost impossible to keep the pistons steamtight. I do not use a hollow hub cast in cylinder, but two disks. I do not use four pistons, but operate with two. Myupper and lower shafts are not geared together for the purpose of transmitting power from theupper shaft to theloweror main driving-shaft, but my shafts as new and desire to secure by Letters Patent 1. In a rotary engine, the combination of a steam-chest H, having two slide-valves, two

cylinders constructed in the form of the figure 8 .and with intersecting peripheries, a case divided by a solid partition, and two disks, L M, all constructed as described, to admit of a joint or separate operation, as specified.

2. The two clyinders E, provided with steaminlet portsin the partition between them, as and for the purpose specified.

3. In a rotary engine, the combination, with two cylinders, substantially as described, of a steam-chest, H, provided with two slide-valves adapted to be operated separately or together, and provided with four ports, two for each cylinder, substantially as shown, and for the purpose specified.

4. The combination, in a rotary engine with two cylinders having steam-ports in their partition,of the disk M, having extension at, with perforations a, as and for the purpose specified.

DAVID O. HOLMAN.

'Witnesses:

THOMAS F. SAUNDERS, ALBERT F. SAUNDERS. 

